REF

1

2

CC

1

IN2

2

V

(R

R )

V

R

V

R

+

-

=

CC

IN1

1

A

IN

1

2

(V

V

) R

V

V

R

R

-

=

+

+

REF

1

2

IN1

2

V

(R

R )

V

R

+

=

17

LPV7215

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SNOSAI6J – SEPTEMBER 2005 – REVISED AUGUST 2016

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Device Functional Modes (continued)

Figure 31. Inverting Comparator With Hysteresis

7.4.5 Noninverting Comparator With Hysteresis

A noninverting comparator with hysteresis requires a two resistor network, and a voltage reference (VREF) at the

inverting input. When VIN is low, the output is also low. For the output to switch from low to high, VIN must rise up

to VIN1 where VIN1 is calculated by Equation 4.

(4)

As soon as VO switches to VCC, VA steps to a value greater than VREF, which is given by Equation 5.

(5)

To make the comparator switch back to its low state, VIN must equal VREF before VA again equals VREF. VIN2 can

be calculated by Equation 6.

(6)

The hysteresis of this circuit is the difference between VIN1 and VIN2, as shown in Equation 7.

ΔVIN = VCCR1/R2

(7)